Digitally printed and produced heat transfer and method of manufacture

ABSTRACT

A digitally produced heat transfer can be manufactured by digitally printing an image onto the protective coating that is receptive to ink and/or toner to form a printed area and an unprinted area of the protective coating, and digitally printing an attractant precisely onto the printed area and not onto the unprinted area. An adhesive powder can be applied onto the printed area and the unprinted area. The adhesive powder can then be removed from the unprinted area and the remaining adhesive powder can be bonded to the printed area. A digitally produced heat transfer can include a protective coating that is receptive to ink and/or toner, a digital image printed onto the protective coating to form a printed area and an unprinted area of the protective coating, an attractant digitally printed precisely onto the printed area, and an adhesive powder applied onto the attractant.

CROSS-REFERENCE TO RELATED APPLICATION(S)

This application claims priority to U.S. provisional patent applicationSer. No. 62/736,093 filed 25 Sep. 2018.

BACKGROUND OF THE INVENTION 1. Field of the Invention

The present invention relates to the creation of photographic qualityheat activated transfers and appliqués and, particularly, to alight-weight printed heat-transfer comprised of numbers, letters, logos,graphics, or other indicia.

2. Description of the Background

Ink-printed heat transfers are well-known and commonly used to transfera graphic, such as text or a figure, onto an item, such as apparel ormerchandise. A transfer sheet or release sheet is usually pre-printedwith a graphic, and then the graphic is transferred from the transfersheet or release sheet to the item using a heated platen, iron or thelike.

To manufacture heat transfers it is typical to apply a release layer tothe transfer sheet before the graphic is printed, then print the inkgraphic atop the release layer, and then coat the adhesive over the topsurface of the graphic. When a user then applies the graphic to theitem, the graphic transfer is turned adhesive-side down onto the itemand heat is applied to the release sheet to transfer the graphic to theitem from the release layer of the release sheet.

Inks and toners can be digitally printed by a variety of methodsincluding static discharge or ink jet printing. Printing techniques suchas gravure printing, offset printing, flexographic printing, screenprinting, and digital printing all can be used to create a heattransfer. In all such processes the thermal adhesive(s) are generallyapplied after the printing process using a screening process, which isnot done in a digital manner. Rather, a template (screen) is required toexpose an area specific to each graphic. This requires an offlinemanufacturing process to create a screen for selectively applying theadhesive, interruption of the digital processes, and thereforesignificantly contributing to the fixed cost of any change in shapebetween graphics and lowering the productivity of the operation byincreasing change-over time. In contrast, the apparel industryincreasingly requires quick-change, low-inventory production of customarticles in small batches with low turnaround time, while keepinginventory at a minimum. Additionally, the offline screen manufacturingprocess is highly reliant on environmentally damaging chemicals.Increasingly customers and brands are seeing value in reducing theenvironmental impact of their products.

New printing methods have evolved such as the HP Indigo® proprietaryliquid electrophotography system to print the graphic. Liquidelectrophotographic (LEP) inks currently used in digital printingpresses typically employ a pigment in a carrier, usually ahydrocarbon-based carrier, such as an isoparaffinic liquid (e.g.,ISOPAR®). The LEP inks include a resin, as well as other ink componentsfor adjusting various desirable properties. The resin holds the pigmenton the print media. However, this method may also rely on screen printedpolymeric coating intermediaries between the printed graphic and theadhesive. The production of screens is a time consumptive process andthe associated clean up and reuse of screens produces undesirableenvironmental harmful waste byproducts that must be disposed.

Until now heat transfer manufacturers have not determined a successfulprocess to provide a fully digital transfer, and therefore they are heldto the aforementioned unattractive large minimum manufacturingquantities. To avoid these large minimums, companies can request a setup charge for small order quantities, which is also undesirable for thecustomer. Significant time and production overhead could be saved ifadhesive could be applied as a step in a fully-digital printing process.

One attempt to do this employs a laser printer to print toner onto asheet. This method then presses an adhesive coated paper to the printwhere the adhesive only sticks to the digitally printed areas, and thenuse those layers in conjunction with an opaque layer as the finaltransfer decoration. See U.S. Pat. No. 8,236,122. Generally, thelaminating conditions used in this process have very small tolerancesthat are not necessarily achievable on a regular basis. Additionally,the processing time to adhere the adhesive to the print is substantial,on the order of 30 seconds per sheet, which cannot compare to the speedof production of a high speed laser or inkjet printing.

An alternative method involves the deposition of adhesive on a releasesubstrate. The deposited adhesive is then pressed in a secondaryprocess, offline to the printing process, onto the toner printed side ofthe printed release liner. See, for example, U.S. Pat. No. 9,227,451issued Jan. 5, 2016. This secondary process is also more timeconsumptive.

What is needed is a more efficient method of digitally printing agraphic and then subsequently fusing a thermal adhesive to the printedgraphic.

SUMMARY OF THE INVENTION

According to embodiments of this invention, a heat transfer and methodfor manufacturing the same can efficiently provide a unique-graphicalhot transfer well suited for customization of apparel and soft goods.

A digitally produced heat transfer can be manufactured by digitallyprinting an image onto a protective coating that is receptive to inkand/or toner to form a printed area and an unprinted area of theprotective coating, and digitally printing an attractant precisely ontothe printed area and not onto the unprinted area. An adhesive powder canbe applied onto the printed area and the unprinted area. The adhesivepowder can then be removed from the unprinted area lacking anyattractant and the remaining adhesive powder can be bonded to theprinted area.

A digitally produced heat transfer can include a protective coating thatis receptive to ink and/or toner, a digital image printed onto theprotective coating to form a printed area and an unprinted area of theprotective coating, an attractant digitally printed precisely onto theprinted area and not onto the unprinted area, and an adhesive powderapplied onto the attractant and not onto the unprinted area of theprotective coating.

BRIEF DESCRIPTION OF THE DRAWINGS

It is, therefore, an object of the present invention to provide afully-digital-printed heat transfer graphic and method of manufacture,to meet the needs of the market for smaller order quantities andcustomized heat transfers produced in a more environmentally friendlyway.

It is yet another object of the present invention to provide a heatsealed appliqué that resembles a traditional, layered appliqué oftenused for lettering and numbering on sports jerseys and uniforms. And itis another object of the present invention to provide a heat sealedappliqué that can be manufactured cost effectively.

The subject matter described and claimed in one embodiment is a processfor producing a digital printed heat transfer comprising the stepsof: 1) obtaining a substrate having a release layer coated on one side;2) digitally printing a graphic layer onto the release layer side of thesubstrate to form a printed area and an unprinted area; 3) digitallyprinting an attractant onto the printed area in registration therewith;4) applying a powder adhesive layer onto the attractant; and 5) bondingthe powder adhesive layer to the attractant and/or the digitally printedgraphic layer. The attractant can precisely secure the adhesive powderto the printed graphical areas, and the unused powder may be removed andrecycled. The adhesive powder can then be fused to the printed graphicby the application of heat and/or pressure via infrared lamps or heatedrollers or a combination thereof. The resulting image can then be cooledto set the image for use as a heat transfer.

Illustrations are provided to disclose aspects of the invention and aredescribed herein. These aspects describe but a few of the ways in whichthe principles disclosed herein can be applied and is intended toinclude all aspects and similar or equivalent methods or steps. Otheradvantages and novel features will become apparent from the followingdetailed description when considered with the drawings.

Other objects, features, and advantages of the present invention willbecome more apparent from the following detailed description of thepreferred embodiments and certain modifications thereof when takentogether with the accompanying drawings in which:

FIG. 1 illustrates a schematic cross sectional view of the preferredembodiment of a digitally produced heat transfer produced using thedescribed method of production.

FIG. 2 illustrates a workflow of manufacture for a digitally producedheat transfer in accordance with the present method.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT

The present invention is process for producing a thermal or “hot”transfer by a multi-stage print process comprising the steps of: 1)obtaining a substrate having a release layer coated on one side; 2)digitally printing a graphic layer onto the release layer side of thesubstrate to form a printed area and an unprinted area; 3) digitallyprinting an attractant onto the printed area in registration therewith;4) applying a powder adhesive layer onto the attractant; and 5) bondingthe powder adhesive layer to the attractant and/or the digitally printedgraphic layer. The powder adhesive may be bound onto and in registrationwith the digitally printed graphic by digitally printing an attractantonto the graphic as an intermediary to secure the adhesive powderthereto. The attractant temporarily and precisely secures the adhesivepowder to the digital print, while excess adhesive powder can be removedand recycled. The temporarily adhering thermal adhesive powder can thenbe heat-fused and more permanently bonded to the digital printed graphicby the application of heat via infrared lamps or heated rollers or acombination thereof. The resulting image may be cooled to set the imagefor use as a heat transfer. The process produces multi-colorphotographic quality heat transfers suitable for the apparel and softgoods industries. With reference to the drawings, the digitally printedheat transfer and method of manufacture is disclosed in more detail.

Referring initially to the drawings, FIG. 1 illustrates adigitally-produced heat transfer 100. The heat transfer 100 generallycomprises a carrier or substrate 102, a release layer 104, and an inkand/or toner receptive coating and protective layer 106 as well as aprotective release liner 114 to protect the heat transfer during storageor transport. The heat transfer 100 also generally comprises one or moreprinted images 108 configured to define one or more graphics and/ortext. The printed image 108 can consist of discontinuous printed areas,adjoined by unprinted area having no printed image. These printed andunprinted areas of the printed image can define printed and unprintedareas of the protective layer 106. In addition, an attractant 110 isprecisely printed onto and in registration to the printed image 108 inthe printed areas. Attractant 110 can include, for example, ionizedwater, a mixture of water and alcohol, an organic solvent, or an oil.The attractant is preferably chemically compatible with the toner or inkand have the ability to be absorbed by the adhesive powder. Typically,the powdered adhesive is a polyurethane that can absorb oil, organicsolvents, water, alcohol, and mixtures thereof. The HP indigo ink forexample is compatible with oil (the toner itself is dispersed insynthetic isoparaffin solvent (Isopar™). The attractant may be adjustedby additives to be specifically compatible with the ink or toner typeprinted on the release liner. The attractant may also require otheradditives depending on the digital printing method used to apply theattractant. Adhesion of the adhesive powder to the printed ink or tonerlayer can be improved by the addition of additives into the attractantlayer. For example, a binder containing amine functionalities willgenerally improve the adhesion between a polyurethane adhesive and theHP indigo toner. An adhesive coating or layer 112 is applied to thedigitally printed graphic 108 and attractant 110. As described below,the adhesive layer 112 can be applied by adhering adhesive powder to thesections of the transfer bearing printed attractant 110, such that ittemporarily binds thereto, and then thermally fusing the bound adhesivepowder to the digitally printed graphic 108 and attractant 110.

Given the foregoing structure the heat transfer 100 may be applied to abase material. The base material can be made using a wide variety oftextile fabrication methods known to the arts including wovens,nonwovens, and knits comprised of natural or synthetic fibers. Furtherthe base material would typically be part of a clothing article orapparel such as tee shirts, jerseys, sweatshirts, outerwear, pants andslacks. More generally, heat transfers produced utilizing this methodcould be applied to soft goods such as apparel, home furnishings,signage such as banners and flags, luggage, back packs and automotiveinteriors. Before the heat transfer 100 is applied to an article therelease liner 114 is removed and the adhesive coating or layer 112 isput in contact with (i.e. is directly adjacent to) the exterior surfaceof the article. Heat and pressure can be applied to the heat transfer100 to bind the adhesive coating/layer 112 to the surface of thearticle, after which the carrier substrate 102 is removed. Protectivelayer 106 that is receptive to ink and/or toner can define the outermost layer of heat transfer 100 after application to the article. Insome embodiments the digital printed graphic 108 and protective layer106 may fuse or otherwise combine when heat transfer 100 is applied tothe article, and the combination can define the outer most layer of theheat transfer 100 after application. The protective layer 106 can be apolymeric film containing amine functionalities, such as polyurethane orpolyamide.

After fusing and heat transfer onto an article of apparel, the digitallyprinted graphic 108, ink receptive coating/protective layer 106 andpowder adhesive 112 ideally have a proportional limit above 2%engineering strain, plus an ability to elongate within a general rangeof 10% to about 50% or more depending on articles of apparel. Oneskilled in the art should understand that certain combinations ofdigital printed graphic methods such as HP Indigo's process wouldprovide such suitable range of elongation. Outerwear and homefurnishings and bags by comparison would generally have a proportionallimit above 1% strain, and an ability to elongate at least about 5% andcould work with electrostatic toner print systems such as those byXeikon® or ink jet printer pigment inks. Those systems by comparisoncrack with substantial elongation. One skilled in the art could utilizesuch systems by breaking larger graphics up into smaller dots tocomprise the image to minimize the degree of elongation around anindividual printed matrix. This would necessitate the need for digitalapplication of the adhesive or an attractant for binding the adhesiveprecisely to the printed element.

FIG. 2 illustrates the method for manufacturing the heat transfer 100 bydigital techniques. The process begins with a section of carriersubstrate 102 coated or laminated on one side with a release layer 104.Preferably, a semi opaque or translucent carrier layer 102 is obtainedthat is already pre-coated with a release layer 104 in either roll orsheet form. The carrier 102 may be cellophane or polyester or the like.Release layer 104 is preferably coated or laminated directly on top ofcarrier substrate 102. Release layer 104 can be a release material thatseparates cleanly from the above-described transferred portion oftransfer 100 but is itself not transferred. Release layer 104 ispreferably a commercially-available “wax” or “non-wax” and“non-silicone” release layer a variety of which are commerciallyavailable from, for example, Mayzo, Inc. of Suwanee, Ga.

At step 200 a combination protectant ink/toner receptive coating 106 isapplied. The toner/ink-receptive coating 106 functions to absorbliquid-based inks, binding the liquid ink until it can fully dry, causethe ink to spread into well-formed dots on the carrier 102. Suitableinked receptive coatings include PrintRite™ ink receptive coatingsavailable from Lubrizol®. Where required, based on ink or toner used,the toner/ink-receptive coating 106 includes or can be modified toinclude a protective coating. One skilled in the art will understandthat the present process is equally suitable for dry toner, but in thisinstance an ink receptive coating 106 is not required.

At step 202 a digital printed ink or toner 108 is applied to thetoner/ink receptive coating 106 using any suitable method of printingfrom a digital-based image.

At step 204 an attractant 110 can be digitally printed onto thedigitally printed graphic 108 in registration therewith. For example, adigital printer can precisely (+/−0.5 mm) print the attractant 110 ontothe printed area of the protective coating. In this manner, the digitalprinter prints attractant 110 substantially onto all of the printedgraphic and does not print attractant 110 substantially onto any ofunprinted area of the protective coating.

At step 206 an adhesive powder 112 is applied to the attractant 110 bymeans of scatter powder coating, direct transfer on a carrier, use of avacuum powder transfer system, or by any other suitable means of powderdeposition. The adhesive powder is preferably a thermally activatedadhesive that can be polyester, polyurethane, polyolefin or polyamidebased. The adhesive powder 112 adheres to the attractant 110 but only tothe attractant 110, not adjacent or surrounding areas. For example, theadhesive powder does not adhere to the carrier layer 102, the releaselayer 104, the ink/toner receptive layer 106, or the digitally printedink/toner layer 108. Thus, in effect, the adhesive powder 112 forms atop layer over the attractant 110 and ink/toner 108 in registrationtherewith.

At step 208 any excess powder is removed from the unprinted surfaceareas of 106 by gravity when rotated around a roller or by any othersuitable means such as mechanical vibration, blowers, or brushes. Thepowder recovered in step 208 is preferably recycled for later use.

At step 210 the remaining adhesive 112 on the digitally printed areas of108 and 110 is more permanently bonded, such as by drying, curing,and/or fusing using heat from infrared IR lamps, ovens, heated rollers,and/or other methods known in the art. The now-bonded adhesive 112 liesin registration over the attractant 110 and ink/toner 108. Depending onthe composition of the attractant used, the attractant layer 110 may byfully evaporated or the attractant layer 110 may have a significantquantity of residual components still present between the digitallyprinted areas 108 and adhesive layer 112 after the completion of step210.

At step 212 the transfer is cooled below the melt point of the adhesivepowder or more preferably to room temperature and a protective releaseliner 114 is applied.

Normal application of the digitally-produced heat transfer 100 occurs atstep 214. The digitally-produced heat transfer 100 may be applied to anyarticle of apparel or soft goods made from textiles. One skilled in theart should understand that the above-described heat transfer 100 can bemade and sold in roll form or sheet form and subsequently cut to size.Application equipment can include heat transfer presses made by GeorgeKnight model DK20SP or Stahl's Fusion® heat press.

The process described above offers a more efficient method of digitallyprinting a hot transfer. The process described can efficiently produce asingle unique graphical transfer or rolls or sheets of same. The heattransfers produced are well suited for customization of apparel and softgoods.

The method would replace processes utilizing screens to apply polymericcoatings and adhesives thus simplifying production, eliminating timeconsumptive changeover processes, and reducing waste and environmentalchemical disposal issues.

Having now fully set forth the preferred embodiment and certainmodifications of the concept underlying the present invention, variousother embodiments as well as certain variations and modifications of theembodiments herein shown and described will obviously occur to thoseskilled in the art upon becoming familiar with said underlying concept.It is to be understood, therefore, that the invention may be practicedotherwise than as specifically set forth in the appended claims.

1. A method for manufacturing a digitally produced heat transfer,comprising: on a protective coating receptive to ink and/or toner,digitally printing an image onto the protective coating to form aprinted area and an unprinted area of the protective coating; digitallyprinting an attractant precisely onto the printed area and not onto theunprinted area; applying an adhesive powder onto the printed area andthe unprinted area; removing the adhesive powder from the unprintedarea; and bonding the remaining adhesive powder to the printed area. 2.The method of claim 1, further comprising applying a release layer ontoa substrate.
 3. The method of claim 2, further comprising applying theprotective coating onto the release layer.
 4. The method of claim 3,wherein the bonding of the remaining adhesive powder to the printed areacomprises drying the adhesive powder to the printed area with at leastone device selected from a group consisting of an infrared lamp, aheated roller, and an oven.
 5. The method of claim 4, wherein thebonding of the remaining adhesive powder to the printed area comprisesfusing the adhesive powder to the printed area with at least one deviceselected from a group consisting of an infrared lamp, a heated roller,and an oven.
 6. The method of claim 5, wherein the bonding of theremaining adhesive powder to the printed area comprises: drying theadhesive powder to the printed area with at least one device selectedfrom a group consisting of an infrared lamp, a heated roller, and anoven; and fusing the adhesive powder to the printed area with at leastone device selected from a group consisting of an infrared lamp, aheated roller, and an oven.
 7. The method of claim 6, further comprisingapplying pressure in the fusing of the adhesive powder to the printedarea
 8. The method of claim 7, further comprising cooling the fusedadhesive powder, the attractant, the printed area, and the unprintedarea.
 9. The method of claim 8, further comprising applying a releaseliner onto the cooled, fused adhesive powder.
 10. The method of claim 1,wherein digitally printing the attractant precisely onto the printedarea and not onto the unprinted area comprises digitally printing theattractant onto substantially all of the printed area and not digitallyprinting the attractant onto substantially any of the unprinted area ofthe protective coating.
 11. The method of claim 1, wherein theattractant comprises at least one selected from a group consisting ofionized water, alcohol, a mixture of water and alcohol, an organicsolvent, and an oil.
 12. The method of claim 1, wherein the adhesivepowder comprises at least one selected from a group consisting ofpolyester, polyurethane, polyolefin, and polyamide.
 13. A heat transfermanufactured by the method of claim 1, wherein, when the heat transferis applied onto a soft outerwear textile, the textile has a proportionalstrain limit greater than two percent and an elongation limit greaterthan ten percent.
 14. A digitally produced heat transfer, comprising: aprotective coating that is receptive to ink and/or toner; a digitalimage printed onto the protective coating to form a printed area and anunprinted area of the protective coating; an attractant digitallyprinted precisely onto the printed area and not onto the unprinted area;and an adhesive powder applied onto the attractant and not onto theunprinted area of the protective coating.
 15. The digitally producedheat transfer of claim 14, further comprising a substrate upon which theprotective coating is applied.
 16. The digitally produced heat transferof claim 15, further comprising a release layer between the substrateand the protective coating.
 17. The digitally produced heat transfer ofclaim 16, further comprising a release liner applied onto the adhesivepowder.
 18. The digitally produced heat transfer of claim 14, whereinthe attractant comprises ionized water.
 19. The digitally produced heattransfer of claim 14, wherein the attractant comprises a mixture ofwater and alcohol.
 20. The digitally produced heat transfer of claim 14,wherein the attractant comprises an organic solvent.
 21. The digitallyproduced printed heat transfer of claim 14, wherein the adhesive powderlayer comprises at least one selected from a group consisting ofpolyester, polyurethane, polyolefin, and polyamide.
 22. The digitallyproduced printed heat transfer of claim 14, wherein, when the heattransfer is applied onto a soft outerwear textile, the textile has aproportional strain limit greater than two percent and an elongationlimit greater than ten percent.
 23. The digitally produced heat transferof claim 14, wherein the attractant comprises an oil.